1. Click on the Folder List view and navigate to the Public Folder Calendar you are wanting to add to your Calendar list.
2. Highlight the Public Folder Calendar.
3. Right click on the Public Calendar and choose Add to Favorites.
3. Click Add.
4. Navigate to the Public Folders --> Favorites and Click on the newly added Public Folder Calendar listed there.
5. The Public Folder Calendar should now show up in your Outlook Calendar List under Other Calendars.
***These steps will also work other Public Folder types as welling like Contacts and Mail-Enabled Public folders, although with the mail-enabled public folder you would right click on the Favorite public folder version and then choose add to Favorites for it to show up in your mailbox favorite area.***